It's to add oxygen to the water and the bio-media to enhance bacteria growth. Not all oxygen is used by the bacterai so the fish benefit also.
It does help, for best results use a limewood airstone (oxymoron?) they produce a finer bubble and therefore more of them in the same area.
Dr Joe
.
It does help, for best results use a limewood airstone (oxymoron?) they produce a finer bubble and therefore more of them in the same area.
Dr Joe
.